opinion

Counterpoint

The article from the Minnesota Soybean Association framing agricultural drain tile as an erosion-prevention practice ("Tile drainage does good, not harm," Opinion, May 27) was scientifically inaccurate and deliberately misleading.

Water-quality professionals and people who follow this issue closely will have quickly read the article for what it was -- an attempt to cast doubt and create uncertainty among those who aren't paying close attention.

This is the playbook that industry always uses when it is threatened. Think tobacco. Think climate change.

The article claimed that drain tile reduces soil erosion by preventing excessive field runoff. While the author was correct in noting that heavily drained fields produce less surface erosion, his argument ignored what happens when all that water comes out the other end of the pipe.

Based on University of Minnesota research, supported by the Minnesota Pollution Control Agency's recent rigorous and extensive study, it is clear that drastic changes to the landscape and its hydrology wrought by agricultural drain tile are the primary factor in the massive increases in Minnesota and Mississippi River pollution.

Intensive row-crop agriculture, combined with wetland loss and drain tiling, are chiefly responsible for the rapid increase in flow-per-unit-precipitation in the Minnesota River.

It is this increased flow that, in turn, has caused a sudden increase in channel erosion and sediment pollution. As a result, Minnesota River sedimentation has increased five-fold since the 1940s.

We've dramatically altered the hydrology of the Minnesota River basin through drain tiles and ditches that are designed to move water off the fields rapidly so the corn and soybeans don't drown.

Instead of percolating slowly into the soil as it once did, all that water now is rushed through a pipe, to a ditch, then to the local ravine or stream, where it has a fire-hose effect, ripping out vegetation, eroding banks and bluffs and carrying dirt (sediment) downstream.

Since the 1940s, this intensive hydrological modification has resulted in the doubling of flows in the Minnesota River near Jordan, while stream and bluff erosion have now replaced field erosion as the largest sources of sediment pollution to the Mississippi and Lake Pepin.

Luckily, solutions to drain-tile erosion, such as conservation drainage practices and improved stream buffer protection, are proven strategies. But these strategies are doomed to fail if big agribusiness continues to peddle half-truths that obscure both the problem and the solutions.

We know that Minnesotans value clean water and recognize that we must all do our part. Many farmers, along with citizens in communities across our state, are working diligently to protect our freshwater resources.

By working together to reduce runoff from cities, farms, factories and feedlots, as well as by addressing the challenges posed by drain-tile erosion, we can all pass a clean-water future to the next generation.

Trevor Russell is watershed program director for Friends of the Mississippi River.